For instance, a laminate film for packaging used for the production of a package bag filled with a material to be packed, which is used in a case of continuously filling and packaging a liquid body, a powdery body or other or a case of discontinuously filling and packaging it, is generally applied to a packaging apparatus at a state of roll-shaped winding through a printing step, a laminating step and a slitter step.
In this case, the slitter step is mainly carried out for cutting and removing side portions of a laminate film to render a width size of the film into a constant value, and adjusting a length of the laminate film wound in roll shape and coupling the laminate films so as to render a total winding length of the laminate film into a given length such as 1000 m, 2000 m or the like, and connecting the laminate films to each other after the cut removal of poor printed portion, poor laminated portion and the like. For this end, 2-3 film coupled portions are frequently existent in the wound laminate film of 2000 m.
Heretofore, the coupling of the laminate films each comprising a base film layer and a sealant layer is carried out by butting a rear end of one laminate film to a front end of another laminate film through an adhesion tape or the like attached to a side of a base film face and joining them.
In the thus coupled laminate film, however, when the laminate film is subjected to longitudinal sealing and lateral sealing at a two folded state in a widthwise direction to form a packaging bag under a fusion of the sealant layer, the adhesion tape or the like made of a material different from the laminate film brings about the increase of the thickness of the laminate film, and also a sufficient heat transmission from a heat sealing blade to the sealant layer is obstructed by the properties inherent to the adhesion tape or the like and hence it is substantially impossible to rapidly melt the sealant layer to an extent enough to the fusing between the mutual sealant layers. For this end, when the continuous filling, packaging and the like are carried out, for example, by applying the laminate film to the packaging apparatus, even if the film coupled portion existing in the free end portion of the folded laminate film could be passed between longitudinal heat sealing blades as a pair of rotational sealing blades rotating at a constant clearance as it is, the sealant layer can not be sufficiently heat-fused even under a heating and pressurizing action of the longitudinal heat sealing blade due to the presence of the adhesion tape or the like, and hence there is a problem that leakage, scattering and the like of the liquid or other material to be packed is caused.
The similar result is also caused by joining with the adhesion tape or the like because end portions of both laminate films can be coupled to each other at a strength required in a packaging bag with a sufficient airtightness or liquid tightness.
Heretofore, the whole of the packaging apparatus or a main part thereof such as heat sealing function part, filling function part and the like is temporarily stopped every the running-out of the coupled portion of the laminate film from the wound film and the coupled portion is passed through the main part of the apparatus and thereafter the filling and packaging are restarted. In the restarting, affirmation of amount of material to be packed in the packaging bag, confirmation of heat sealing position and sealed state, confirmation of cutting position of the packaged bag and forming position of tear notch, and so on are conducted to put all of them into acceptable ranges, and thereafter the apparatus is really re-worked.
Therefore, many times and operating numbers are required form a temporary stop of the apparatus or a main function part thereof to a re-working of the apparatus, which cause a serious problem in the working capacity and efficiency, while it is obliged to consume greater amounts of the laminate film and the material to be packed, which causes a problem of lowering the material yield.
For this end, the invention provides a coupling structure, a coupling method and a coupling apparatus of a laminate film, in which end portions or side portions of laminate films are coupled to each other without using a coupling material such as an adhesion tape or the like and the resulting coupled portion is sufficiently contributed to make a packaged bag likewise the other portion of the laminate film and also a tensile strength required in the laminate film is given to the coupled portion, whereby the capacity and efficiency of the filling and packaging work for the material to be packed can effectively be enhanced and the yield of the material can be largely improved.